Rolling mills



Feb. 16, 1965 R. B. SIMS 3,169,423

ROLLING MILLS Filed Nov. 50, 1960 4 Sheets-Sheet 1 Hal.

INVENTOR AYMOND B. Sms

ATTOQNEY Feb. 16, 1965 R. B. SIMS 3,169,423

ROLLING MILLS Filed Nov. 30, 1960 4 Sheets-Sheet 2 F/GZ.

INVEN'TOR RAYMOND B. Sms

ATT RNEY Feb. 16, 1965 R. B. SIMS 3,169,423

ROLLING MILLS Filed Nov. 30, 1960 4 Sheets-Sheet 3 Flat lmveN-roe RAYMOND B. Sums ATTORNEY Feb. 16, 1965 R. B. SIMS 3,169,423

ROLLING MILLS Filed Nov. (50, 1960 4 Sheets-Sheet 4 3/ .O O3/ K I 30 4 30 3/ III 5:: \1/

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INvENToQ RAYMOND B Sums 7L Q flux;

ATTORNEY United States Patent 3,169,423 RQLLING MILLS Raymond Bernard Sims, Sheilield, England, assignor to Davy and United Engineering Company Limited, Yorkshire, England Filed Nov. 30, B50, Set. I o. 72,783 Claims priority, application Great Britain, Dec. 3, 1959, 41,104/59 Claims. (ill. 80-38)- This invention relates to rolling mills and is particularly concerned with a cluster mill of the type in which each work roll is backed up by one or more sets of intermediate rolls and in which the final thrust is transferred to the frame through a set of back-up rolls engaging with the set of intermediate rolls or the last set of such rolls. T he riving power for the mill may conveniently be transmitted through the intermediate rolls.

Cluster mills are particularly useful for the rolling of very hard materials and have the advantages that, as the work rolls are supported along their length, work roll bending is kept to a minimum and the diameter of the rolls may be consequently very small, thereby reducing both the load and the torque required for rolling. Cluster mills also permit rolling to much thinner gauges.

Previous forms of cluster mills have been employed as back-up rolls shafts having castors spaced along their lengths and engaging, on the one hand, the intermediate rolls, and on the other hand, a part of the mill frame. By having a large number of castors for each back-up roll the thrust could be transferred to the frame over the whole width of the mill.

The use of back-up castors complicates the design of the mill as a whole and does not produce a uniform transference of thrust to the frame over the whole length of the rolls. Moreover there is not a free choice of lubricant.

In accordance with the present invention, the back-up rolls are cylindrical and are carried in hydrostatic bearings extending over at least a substantial part of the length of the back-up rolls and transferring the thrust from the rolls to the mill frame.

By use of hydrostatic pad bearings, the thrust is transferred to the frame uniformly over the width of the mill, thereby preventing any bending of the work rolls. This is achieved without complicating the mill design.

Any convenient liquid may be pumped continuously to the pad bearings, the pressure of the liquid maintaining the required clearances between the back-up rolls and the bearing structure. As the back-up rolls do not contact the work directly, the amount of wear in the back-up rolls is unsubstantial and therefore the rate of leakage from the bearings past the Work rolls does not appreciably increase with time. When the wear has grown substantial, the diameters of the back-up rolls may be restored by resurfacing with, for example, hard chromium.

The passage of liquid from the pad bearings past the back-up rolls assists in the extraction of heat from the mill and for this reason the mill of the present invention may be run at higher rates than previous cluster mills. Preferably, the liquid pumped to the bearings is a waterbased soluble oil which facilitates the removal of heat.

In one cluster mill according to the invention, each work roll is backed up by two intermediate rolls which, in turn, are backed up by three back-up rolls. Each of the backup rolls is carried in a hydrostatic bearing consisting of a bearing member extending round a large part of the periphery of the back-up roll but leaving unobstructed the engagement of the backup roll with the intermediate roll or rolls and over the whole length of the back-up roll. The bearing member has a number of recesses in its internal surface but elsewhere the clearance between the bearing member and the back-up roll is very small indeed.

Oil under high pressure is supplied by a pump to the re-- cesses in each bearing member, leakage being limited by the narrowness of the clearances between the bearing members and the back-up rolls.

The invention will be more readily understood by way of example from the following description of a cluster mill in accordance therewith, reference being made to the accompaying drawings in which:

FIGURE 1 is a perspective view of the mill;

FIGURE 2 is a sectional view takeout right angles to the axes of the rolls and showing the work rolls in contact;

FIGURE 3 is a view similar to that of FIGURE 2, but showing the work rolls at maximum separation;

FIGURE 4 is a development of one of the hydrostatic bearing surfaces, and

FIGURE 5 shows diagrammatically the supply of liquid to the hydrostatic bearings.

Referring to the FIGURES 1 to 3, the mill has a one piece housing 12, which has a lengthwise cylindrical opening 13 therein. A pair of part-cylindrical members 14, 14' are located within the opening 13. r

The small work rolls 15,15 are backed up by pairs of intermediate rolls 16, 16',-Wl1ich,v in turn, are located by the back-up rolls 17, 17'. Back-up rolls 17, 17' are plain cylinders without necks and are carried in the members 14-, 14' by hydrostatic bearings 18, 18'. The members 14, 14- are rotatable within the housing 12 and can be turned by means of the screws 20 and 20' which operate in the nuts 21 and 21 and act on members 14, 14' through shoes 22, 22 and pressure blocks 23,23. The members lo, 14 are biased apart by spring means 24 engaging the members; the spring means 24 may be hydraulic, pneumatic or mechanical in operation. The line of centres of the two work rolls, 15, 15' is displaced from the centre 25 of the opening 13, so that operation of the screws 2t), 20' results in relative movement of the members 14, 14' and separation of the work rolls from the iii-contact position shown in FIGURE 2 to the position shown in FIGURE 3 in which the work rolls are at maximum separation. The work enters and leaves the mill through slots 26, 27 located in the side of the housing 12 and is guided to and away from the work rolls 15, 15 by guide plates 28, 28 secured to the inner faces of the members 14, 14'.

Each of the hydrostatic bearings 18 has two pairs of pockets 36 located as shown in FIGURE 4. The two pairs are spaced apart along the length of the back-up roll 17, and the pockets 30 of each pair are spaced apart around the periphery of the back-up roll 17. Apart from the pockets 3%, the clearance between the bearings 18 and the back-up rolls 17 is very small. Each of the pockets 39 is supplied with liquid under pressure-through oil supply holes 31 (FIGURE 4), leakage past the back-up rolls 17 being limited by the narrowness of the clearances between the bearings 18 and the rolls 17. While four pockets 30 per bearing 18 is illustrated in the drawings, the number of pockets may be varied according to the length and diameter of the back-up rolls 17.

The supply of liquid to the pockets 3t? of the six bearings 18 shown in FIGURES 2 and 3 is illustrated in FIGURE 5. There is a separate pump 35 for each hearing, each pump drawing liquid from a reservoir 36 and pumping the liquid through four lines 37 individually to the four supply holes 31 of the four pockets 30. Each line 37 has a flow control valve 38 for individual control of the supply of liquid to each of the pockets 30. The liquid draining from the bearings is collected in a drain tank 49, and pumped 'back to the reservoir 36 through a filter 41 and a cooler 42 by a pump 43.

An individual pump 35 for each bearing 18 is supplied because the loading on the bearings may vary according to their location. However, if desired, there may be a single pump taking the place of the six pumps 35 and supplying the bearings through individual pressure regulators. V Y

By having more than one pocket 30 round each backup roll 17, the roll 17 isa'utomatically centered within its bearing 18. 'Also, where thereja number of pockets 30 along the length of the roll 17, the pressure supplied to pockets along the length of the roll maybe varied in i order to adjust the roll for shape correction;

The leakage of liquid from the pockets 3%) pastthe rolls 17 extracts oil from the mill, thereby enabling it to run at a high rate. Any convenient liquid may be pumped to the pockets, but it is preferred to use a waterbased soluble oilfor heat extraction "purposes.

1 Although the drawings illustrate a single 'set of intermcdi-aterolls 16, 16 between the work rolls 15,15 and 1 the back-up rolls 17, 17 a further set of intermediate rolls may be located between 'each'set of intermediate rolls and "the final back-up rolls; in this'case, of course, the second set of intermediate rolls is constitued by three rolls and the back-up'ro11s for each work roll are four in number. Power for drawing the strip through the mill may be supplied by driving the intermediate rolls or by applying tension to the outgoing strip or by a combination of these methods.

For larger cluster mills, a one piece housing, such as that illustrated at 12,-rn'ay not-be feasible. In this case,

each of the lastback-uprolls may be "supported by four to eight, for example, hydrostatic bearings for each roll. The pressure pockets of these hearings would be formed being interposed between said back-up rolls and said frame each bearing member extends through a large are around,

either directly. into arnassive cross beam of the mill housing or in a' separate piece which is bolted firmly to the cross beams of the housing. In vany event, the bear:

2 V ings for the back-up rollsare capable of taking thetransverse thrust applied by the work rolls to the back-up rolls, as Well as the vertical thrust.

. In accordance'withthe provis'i-o'ns'o'f the patent statutes, I have explained the principle and operation of my invention and have illustrated and described what I consider to represent the best embodiment thereof. However, I desire to have it understood that withinthe scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

I claim:

for transferring thrust generated during rolling to said 'frame, and said members being movable relative .to each other for adjustment of the gap between the work rolls. 2. A cluster rolling mill according to claim 1, in which each hydrostatic bearing comprises a bearing member rigidly secured to the first and second members and having a plurality of recesses in its bearing surface communicating with liquid-supplying passages.

3. A cluster rolling mill according to claim 2, in which its back-up roll but leaves unobstructed the engagement of that b ack-up roll with the contacting intermediate roll.

4. A cluster rolling mill according to claim 1, in which the first and second members are part-cylindrical and are slidably arranged in a cylindrical opening in a housing, the work-rolls being eccentrically placed with respect to the opening so that rotational movement of one member relative to the other in the opening etfects adjustment in the gap between the work rolls. f i

V 5. A cluster rolling mill according to claim 4, in which i there are spring means biasing apart adjacent ends of thetwo members and screws acting independently on the .members to determine the position of each member.

References (Iited in the file of this patent UNITED STATES PATENTS 977,725 Gautschi Dec. 6, 1910 1,519,657 Biggert Dec. 16, 1924 2,085,449 ROhIl June 29, 1937 2,187,250 Sendzirnir Jan. 16, 1940 2,660,485 Gerard Nov. 24, 1953' 2,709,627 Peterson May 31, 1955 Macks May 17, 1960 

1. A CLUSTER MILL COMPRISING A MILL FRAME, A PAIR OF WORK ROLLS, AT LEAST ONE SET OF INTERMEDIATE ROLLS FOR EACH WORK ROLL, A SET OF CYLINDRICAL BACK-UP ROLLS FOR EACH WORK ROLL, HYDRAULIC BEARINGS FOR THE BACK-UP ROLLS EXTENDING OVER AT LEAST A SUBSTANTIAL PART OF THE LENGTH OF THE BACK-UP ROLLS, A FIRST MEMBER FOR CARRYING THE BEARINGS OF ONE SET OF BACK-UP ROLLS, A SECOND MEMBER FOR CARRYING THE BEARINGS FOR THE OTHER SET OF BACK-UP ROLLS, SAID MEMBERS BEING INTERPOSED BETWEEN SAID BACK-UP ROLLS AND SAID FRAME FOR TRANSFERRING THRUST GENERATED DURING ROLLING TO SAID FRAME, AND SAID MEMBERS BEING MOVABLE RELATIVE TO EACH OTHER FOR ADJUSTMENT OF THE GAP BETWEEN THE WORK ROLLS. 